The previous commit for this ticket left the code in a working state.
However, it was not possible for image management to distinguish between
the test and permanent states.
Now, these two states are indicated by the addition of a new swap type:
BOOT_SWAP_TYPE_PERMANENT.
Currently, to permanently run the alternate image, the boot loader
requires the following sequence:
1. image test <slot-01-hash>
2. reboot
3. image confirm
The new feature is to remove the need for the third step. The user
should be able to permanently switch images with this sequence:
1. image confirm <slot-01-hash>
2. reboot